1. Field of the Invention
The present invention relates to a lead cutting apparatus of an electronic component and more particularly to a lead cutting apparatus of an electronic component such as a packaged integrated circuit (IC), in which the leads extending from each end of a package of the component are cut to a specific length.
2. Description of the Prior Art
In recent years, the semiconductor industry has been in the process of transition from the era of mass-production of a same product to the era of small-quantity production of various products with the progressing expansion and competition of purpose or use. Accordingly, there has been the increasing need of flexible manufacturing systems (FMSs) capable of the small-quantity production of various products in the manufacturing system field of semiconductor devices or ICs.
In a finishing process (for example, a lead cutting or lead forming process) of ICs, which is performed after an assembling process, a proper cutting or forming die has been usually used for enabling automatic cutting or formation of the leads of the IC. However, various products necessitate various sizes or lengths of the leads. As a result, to cope with the various lead sizes or lengths, a lot of dedicated dies need to be prepared in advance.
FIG. 1 shows an example of the conventional lead cutting apparatuses of an IC.
In FIG. 1, the conventional apparatus includes a table 104 on which a work piece or a packaged IC 111 is placed. The table 104 is fixed on a base 112. The IC 111 has an encapsulation package 110 and leads 110a protruding from each side or end of the package 110.
A hole 104a is formed in the top surface of the table 104. The hole 104a is designed to have a shape allowing the metal, plastic, or ceramic package 110 of the IC 111 to be fitted into the hole 104a. At this time, the horizontally-extending leads 110a of the IC 111 are outside the hole 104a.
A pair of punching units 107A and 107B are provided on the base 112 at each side of the table 104. The pair of punching units 107A and 107B serve to cut the leads 110a of the IC 111 to a specific desired length. The pair of punching units 107A and 1073 are horizontally movable toward the table 104 and away from the table 104 along horizontally-extending guides 121 that are fixed on the base 112. The movement of the pair of punching units 107A and 107B are realized by a pair of driving or moving mechanisms 103A and 103B, respectively. The pair of driving mechanisms 103A and 103B are provided in the vicinities of the pair of punching units 107A and 107B, respectively.
Since the pair of punching units 107A and 107B have the same configuration, the configuration of the unit 107A is explained here. The punching unit 107A has a gripper 106 formed by a movable gripping member 106a and a fixed gripping member 106b. The movable gripping member 106a is vertically movable along guides 122. The leads 110a of the IC 111 are sandwiched and positioned by the gripping members 10a and 106b. The punching unit 107A further has a punch 105 serving as a cutter for the leads 110a. The guide 122 may be omitted.
The movable gripping member 106a is moved by the combination of an electric motor 113, feed screws 118, and nuts 119. The motor 113 is fixed to the body of the punching unit 107A. The screws 118 are rotated by the motor 113. The nuts 119 are engaged with the corresponding screws 118. The vertical movement of the movable gripping member 106a is realized by rotation of the screws 118 generated by the motor 113.
Because the pair of driving mechanisms 103A and 103B have the same configuration, the configuration of the mechanism 103A is explained here. As seen from FIG. 1, the driving mechanism 103A has a feed screw 108 engaged with the body of the unit 107A and a motor 109 fixed onto the base 112. The screw 108 is rotated by the motor 109. The punching unit 107A is horizontally moved toward the table 104 and away from the table 104 by rotation of the screw 108.
The conventional lead cutting apparatus shown in FIG. 1 operates as follows.
First, the packaged IC 111 is positioned on the table 104 by fitting the package 110 into the hole 104a of the table 104. Next, the pair of punching units 107A and 107B are horizontally moved toward the table 104 by the pair of driving mechanisms 103A and 103B at specific distances, respectively. Thus, the punching units 107A and 107B are positioned at desired positions for preset specific lengths, respectively. At this stage, the leads 110a are located on the fixed gripping members 106b.
Subsequently, the movable gripping members 106a of the grippers 106 of the pair of punching units 107A and 107B are lowered toward the fixed gripping members 106b, thereby gripping the leads 110a of the IC 111 at each side of the table 104. Finally, the punches 105 of the punching units 107A and 107B are lowered to cut the gripped leads 110a to the desired length. These operation sequence is performed under the control of a programmed controller (not shown).
As described above, with the conventional lead cutting apparatus shown in FIG. 1, the leads 110a can be automatically cut to the desired specific length. However, the hole 104a of the table 104 is formed to be dedicated to the shape and size of the package 110 of the IC 111. Therefore, there is a problem that the conventional apparatus cannot be used for another IC with a different shape and/or a size.
To make it possible for the conventional apparatus to cut the leads of various ICs with different size and/or shapes, a lot of dedicated tables 104 having various holes 104a are necessarily prepared. Thus, there arises another problem that the number of the tables 104 increases and consequently, the initial and management costs are raised.
Especially, the sort of the ICs is frequently changed in the small-quantity production of various products. Accordingly, it takes a long time for set-up work such as table exchange and table centering, decreasing the operating efficiency of the apparatus.
Moreover, an automatic IC feeder is usually equipped with the lead cutting apparatus of this sort. In this case, the conventional apparatus necessitates the IC feeder an insertion behavior of the package 110 of the IC 111 into the hole 104a of the table 104. This behavior increases the cycle time.